Efficient Production, Purification and Characterization of Therapeutically Significant L-Asparaginase from Bacillus licheniformis ASN51

asparaginase (L-ASNase) is a versatile anticancer and acrylamide reducing enzyme used in medical and food industries. Exploration of new sources of L-asparaginase is in demand due to immunogenic issues, short half-life and narrow range of pH and temperature stability of available formulations. The present study describes extracellular Type II L-ASNase production from soil Bacillus licheniformis ASN51 strain. Optimized asparaginase production with a specific activity of 499 U mg(-1) was obtained at pH 8 and 37 degrees C in M9 medium containing 0.2% glucose and 1% L-asparagine. L-ASNase was precipitated using acetone and purified through Sephadex G-100 column yielding 61.2 and 34% recovery, respectively. The purified asparaginase has a molecular mass of 38 kDa and specific activity of 8,333 U mg-1. L-ASNase showed stability at a wide range of pH (4-9) and temperature (10-50 degrees C) while retained 100% of its activity for 24 h at 37 degrees C, pH 7. Enzyme kinetics revealed a Vmax of 7750 U and Km of 0.04 mM. Purified L-ASNase from B. licheniformis ASN51 showed antioxidant activity (IC50 value 53.1 mu g mL(-1)) against 2, 2- diphenyl-1-picrylhydrazyl (DPPH) radical and anticancer activity (53.3%) against HepG2 cell line. To the best of knowledge, among reported strains of B. licheniformis, ASN51 is the highest asparaginase producing strain. Purified L-ASNase showed long-term stability at physiological pH and temperature indicating its suitability for therapeutic applications.